Long-Term Follow-Up of Oral Administration of Flavonoids, Centella asiatica and Melilotus, for Diabetic Cystoid Macular Edema Without Macular Thickening

The protective effects of flavonoids and carotenoids against diabetic complications-A review of in vivo evidence

Diabetes mellitus is a chronic metabolic disorder caused either by inadequate insulin secretion, impaired insulin function, or both. Uncontrolled diabetes is characterized by hyperglycemia which over time leads to fatal damage to both macro-and microvascular systems, causing complications such as cardiovascular diseases, retinopathy and nephropathy. Diabetes management is conventionally delivered through modifications of diet and lifestyle and pharmacological treatment, using antidiabetic drugs, and ultimately insulin injections. However, the side effects and financial cost of medications often reduce patient compliance to treatment, negatively affecting their health outcomes. Natural phytochemicals from edible plants such as fruits and vegetables (F&V) and medicinal herbs have drawn a growing interest as potential therapeutic agents for treating diabetes and preventing the onset and progression of diabetic complications. Flavonoids, the most abundant polyphenols in the human diet, have shown antidiabetic effects in numerous in vitro and preclinical studies. The underlying mechanisms have been linked to their antioxidant, anti-inflammatory and immunomodulatory activities. Carotenoids, another major group of dietary phytochemicals, have also shown antidiabetic potential in recent in vitro and in vivo experimental models, possibly through a mechanism of action similar to that of flavonoids. However, scientific evidence on the efficacy of these phytochemicals in treating diabetes or preventing the onset and progression of its complications in clinical settings is scarce, which delays the translation of animal study evidence to human applications and also limits the knowledge on their modes of actions in diabetes management. This review is aimed to highlight the potential roles of flavonoids and carotenoids in preventing or ameliorating diabetes-related complications based on in vivo study evidence, i.e., an array of preclinical animal studies and human intervention trials. The current general consensus of the underlying mechanisms of action exerted by both groups of phytochemicals is that their anti-inflammatory action is key. However, other potential mechanisms of action are considered. In total, 50 in vivo studies were selected for a review after a comprehensive database search via PubMed and ScienceDirect from January 2002 to August 2022. The key words used for analysis are type-2 diabetes (T2DM), diabetic complications, flavonoids, carotenoids, antioxidant, anti-inflammatory, mechanisms of prevention and amelioration, animal studies and human interventions.

From Oxidative Stress to Inflammation in the Posterior Ocular Diseases: Diagnosis and Treatment

Most irreversible blindness observed with glaucoma and retina-related ocular diseases, including age-related macular degeneration and diabetic retinopathy, have their origin in the posterior segment of the eye, making their physiopathology both complex and interconnected. In addition to the age factor, these diseases share the same mechanism disorder based essentially on oxidative stress. In this context, the imbalance between the production of reactive oxygen species (ROS) mainly by mitochondria and their elimination by protective mechanisms leads to chronic inflammation. Oxidative stress and inflammation share a close pathophysiological process, appearing simultaneously and suggesting a relationship between both mechanisms. The biochemical end point of these two biological alarming systems is the release of different biomarkers that can be used in the diagnosis. Furthermore, oxidative stress, initiating in the vulnerable tissue of the posterior segment, is closely related to mitochondrial dysfunction, apoptosis, autophagy dysfunction, and inflammation, which are involved in each disease progression. In this review, we have analyzed (1) the oxidative stress and inflammatory processes in the back of the eye, (2) the importance of biomarkers, detected in systemic or ocular fluids, for the diagnosis of eye diseases based on recent studies, and (3) the treatment of posterior ocular diseases, based on long-term clinical studies.

Effects of Flavonoid Supplementation on Common Eye Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

Background: Emerging studies show that certain plant compounds may reduce the severity of most prevalent ocular abnormalities. The aim of this systematic review and meta-analysis was to assess the effect of dietary flavonoids on major eye disorders.

Methods: Eligible studies were identified by searching PubMed, Web of Science, Scopus, and Cochrane Library databases for all articles published up to April 2021. The literature search yielded 1,134 articles, and a total of 16 studies were included in the systematic review. A meta-analysis of 11 intervention trials involving a total of 724 participants was performed.

Results: Using a random-effects model, the pooled results revealed an overall significant effect of flavonoids on common ophthalmic disorders (standard mean difference = −0.39; 95% CI: −0.56, −0.21, p < 0.01). Of the subclasses of flavonoids, flavan-3-ols (standard mean difference = −0.62; 95% CI: −1.03, −0.22, p < 0.01), and anthocyanins (standard mean difference = −0.42; 95% CI: −0.63, −0.21, p < 0.01) were the only effective intervention for improving the outcomes of ocular conditions. For several of the other flavonoid subclasses, evidence on efficacy was insufficient.

Conclusion: Our findings indicate that flavonoids may improve the clinical manifestations associated with ocular disorders. However, further well-constructed clinical trials are required to confirm these results and examine the effect of flavonoids on eye disorders other than those identified in this review.

Systematic Review Registration: PROSPERO, identifier CRD42021247332.

Ethnobotany, Phytochemistry and Pharmacological Features of Centella asiatica: A Comprehensive Review

Centella asiatica (CA) or Gotu cola is an herbal plant from the Apiaceae family with a long history of usage in different traditional medicines. It has long been used for the treatment of various ailments such as central nervous system (CNS), skin and gastrointestinal disorders especially in the Southeast Asia. This chapter focused on the phytochemical constituent and pharmacological activities of CA based on preclinical and clinical studies. Additionally, botanical description and distribution, traditional uses, interactions, and safety issues are reviewed. Electronic databases of Google Scholar, Scopus, PubMed, and Web of Science were searched to obtain relevant studies on the pharmacological activities of CA. Approximately, 124 chemical compounds including triterpenoids, polyphenolic compounds, and essential oils have been isolated and identified from CA. Ethnomedicinal applications of CA mostly include treatment of gastrointestinal diseases, wounds, nervous system disorders, circulatory diseases, skin problems, respiratory ailments, diabetes and sleep disorders in various ethnobotanical practices. Pharmacological studies revealed a wide range of beneficial effects of CA on CNS, cardiovascular, lung, liver, kidney, gastrointestinal, skin, and endocrine system. Among them, neuroprotective activity, wound healing and treatment of venous insufficiency, as well as antidiabetic activity seem to be more frequently reported. At the moment, considering various health benefits of CA, it is marketed as an oral supplement as well as a topical ingredient in some cosmetic products. Additional preclinical studies and particularly randomized controlled trials are needed to clarify the therapeutic roles of CA.

The Benefits of Flavonoids in Diabetic Retinopathy

Diabetic retinopathy (DR), one of the most common complications of diabetes, is the leading cause of legal blindness among adults of working age in developed countries. After 20 years of diabetes, almost all patients suffering from type I diabetes mellitus and about 60% of type II diabetics have DR. Several studies have tried to identify drugs and therapies to treat DR though little attention has been given to flavonoids, one type of polyphenols, which can be found in high levels mainly in fruits and vegetables, but also in other foods such as grains, cocoa, green tea or even in red wine. Flavonoids have anti-inflammatory, antioxidant and antiviral effects. Since it is known that diabetes induces oxidative stress and inflammation in the retina leading to neuronal death in the early stages of the disease, the use of these compounds can prove to be beneficial in the prevention or treatment of DR. In this review, we summarize the molecular and cellular effects of flavonoids in the diabetic retina.

The Coming Age of Flavonoids in the Treatment of Diabetic Complications

Diabetes mellitus (DM), and its micro and macrovascular complications, is one of the biggest challenges for world public health. Despite overall improvement in prevention, diagnosis and treatment, its incidence is expected to continue increasing over the next years. Nowadays, finding therapies to prevent or retard the progression of diabetic complications remains an unmet need due to the complexity of mechanisms involved, which include inflammation, oxidative stress and angiogenesis, among others. Flavonoids are natural antioxidant compounds that have been shown to possess anti-diabetic properties. Moreover, increasing scientific evidence has demonstrated their potential anti-inflammatory and anti-oxidant effects. Consequently, the use of these compounds as anti-diabetic drugs has generated growing interest, as is reflected in the numerous in vitro and in vivo studies related to this field. Therefore, the aim of this review is to assess the recent pre-clinical and clinical research about the potential effect of flavonoids in the amelioration of diabetic complications. In brief, we provide updated information concerning the discrepancy between the numerous experimental studies supporting the efficacy of flavonoids on diabetic complications and the lack of appropriate and well-designed clinical trials. Due to the well-described beneficial effects on different mechanisms involved in diabetic complications, the excellent tolerability and low cost, future randomized controlled studies with compounds that have adequate bioavailability should be evaluated as add-on therapy on well-established anti-diabetic drugs.

Effect of a mixture of diosmin, coumarin glycosides, and triterpenes on bleeding, thrombosis, and pain after stapled anopexy: a prospective, randomized, placebo-controlled clinical trial

PURPOSE

We evaluated the efficacy of oral administration of a mixture of diosmin, coumarin glycosides, and Centella asiatica (Venoplant®) in preventing bleeding, pain, and thrombosis of internal and external hemorrhoids after stapled anopexy (SA).

METHODS

SA was conducted in 182 patients with third-degree hemorrhoids. Preoperatively, patients were randomized evenly into two groups. Group A patients were administered Venoplant for 30 days post-SA, and group B received a placebo for 30 days post-SA. Patients received paracetamol for postoperative pain. Visit (v)1, v2, and v3 took place 7, 15, and 30 days postoperatively, respectively; bleeding (clinical examination), visual analog scale (VAS), thrombosis (clinical examination), and pain (paracetamol dosage, VAS) were evaluated.

RESULTS

At v1, v2, and v3, the numbers of patients with bleeding in groups A and B were 21 and 46, 3 and 25, and 1 and 5, respectively (p < 0.05). At v1, v2, and v3, the numbers of patients in groups A and B with thrombosed internal hemorrhoids were 3 and 13, 2 and 11, and 1 and 8, respectively (p < 0.05). The number of patients who took at least one paracetamol tablet was similar in both groups at v1 but was significantly greater in group B than group A at v2 and v3 (p < 0.05); pain VAS scores were equivalent at v1 and significantly greater in group B than group A at v2 and v3 (p < 0.05).

CONCLUSIONS

Venoplant effectively reduced bleeding after SA, decreased the incidence of thrombosed internal hemorrhoids, and decreased postoperative pain.

Nutritional supplements in age-related macular degeneration

Age-related macular degeneration (AMD) is the most frequent cause of blindness in the Western World. While with new therapies that are directed towards vascular endothelial growth factor (VEGF), a potentially efficient treatment option for the wet form of the disease has been introduced, a therapeutic regimen for dry AMD is still lacking. There is evidence from several studies that oral intake of supplements is beneficial in preventing progression of the disease. Several formulations of micronutrients are currently available. The present review focuses on the role of supplements in the treatment and prevention of AMD and sums up the current knowledge about the most frequently used micronutrients. In addition, regulatory issues are discussed, and future directions for the role of supplementation in AMD are highlighted.